Is your differences or similarities the glue that keeps your relationship strong?

I always thought the similarities and shared interests were the main basis for a strong relationship. Until I talked to an old friend I have not seen in years. Her relationship with her husband is held together and strengthened by their differences. She was telling me it keeps the relationship fresh and conversation and interests in each other strong. I need to process this and try to figure this one out.

the guy I'm dating brought that up in conversation. he also said that someone w/ the same interests would be boring & not bring anything new to the relationship. I can see that reasoning. never thought about things that way until that conversation.

It's both, most of the time, it's our differences. He just keeps me on the road otherwise I would wander off in to the forest. He is a few years older, keeps me in check & is my voice of reason. He is more opposite, he likes to stay around the house, I like going out. He believes in hard work & I'm too lazy. He hates noise & I blast the stereo.
We have similar interests; like the love of riding motorcycles, love of sex, watching old movies, spending time together walking around & talking about what ever comes to mind. Then again he does most of the listening & I do most of the talking...differences, keeps our relationship strong.

My partner and i have similar intrest that are very important to us, which i think is partly why we get along so well. I find it's worked out much better, for me, than other relationships where my former partners and i only had few/limited common intrest, which had a tendency to lead to bad communication since there was less for us to agree on or do together. While my partner and i do have our differences - like how i enjoy modifying my body with piercings, tattoos, and through my hair and they hate it and find it to be "stupid" - we tend to agree on/care about more things than disagree and i think thats what makes our relationship so strong.
We enjoy doing a lot of the same things: eating the same things, like the same type of music (which is a VERY big thing for me), have very similar political views, and also enjoy expanding/exploring our common intrest. It makes it much easier to communicate with him and find more things to do together for these reasons than it has been with others in the past.

In my relationship it is our differences that keep us going. We are total opposites in every aspect including interests and philosophy. This keeps things interesting and new. It allows our conversations to be varied and also our outlooks and desires to constantly be bringing in fresh ideas. While there are times that I wish I could share some of my interests with my partner I wouldn't trade it for anything.

Both - we share values and faith - but are very different in other areas. The differences make be confidants more fruitful. She can come to me with problems at work and I can give her a completely different perspective - and it's better that the help comes from someone that you know, trust and even love.

For her part - she has always had a minimal interest in sex - while I've been obsessed with it. To her great benefit she's grown to be very easily multi orgasmic - including gushing. She's quite grateful because she knows how good she has it compared to her friends. And it's great job security for me!